Sudden braking apparatus for press

ABSTRACT

The present invention discloses a sudden braking apparatus for a press comprising a driving motor ( 6 ), a flywheel ( 5 ) connected to the motor through a pulley ( 7 ) and a belt ( 8 ), a small gear ( 9 ) connected to the flywheel through a rotational shaft ( 3 ) installed horizontally to a supporting frame ( 2 ), a large gear ( 10 ) engaged with the small gear and installed on a crankshaft ( 11   b ) of the press, and a cam ( 14 ) mounted at the crankshaft ( 11   a,    11   b ) and connected to a slide-block ( 12 ) via a crank rod ( 13 ), characterized in that the apparatus comprises a circular guide ( 19 ) slidably connected to the crankshaft ( 11   b ) and having a brake lining ( 16 ) on one side of the guide ( 19 ) facing the supporting frame ( 2 ), a radial toothed gear ( 18 ) on the other side of the guide and a tapered groove ( 15 ) extending from the circumference. In addition the apparatus includes a clutch plate ( 22 ) shifting device which enables the circular guide ( 19 ) to move horizontally.

FIELD OF THE INVENTION

The present invention relates to a power press, in particular to asudden braking apparatus for the power press, to prevent accidentsduring the operation of the press by making it possible toinstantaneously stop the operation of the press.

BACKGROUND OF THE INVENTION

In general, the press is typically a dangerous machine which causesindustrial accidents in the field of manufacturing. Even thoughpresently the number of industrial accidents is decreasing, the rate ofaccidents due to presses is not decreasing, and therefore acountermeasure to rectify this problem is required.

Furthermore, because conventional presses are mostly pin-clutch types,even if such circumstances as a finger of operator getting into thepress mold owing to carelessness on the part of the operator arise, theoperation of the conventional press cannot be stopped suddenly. A press,which is composed of an air-clutch enabling the press to stopinstantaneously using a sensor such as an infrared beam switch, iswidely known to prevent the above problem in the event of such dangeroussituations. However, as the price of such a press is high, it isdifficult for small-scale manufacturing companies to purchase it.

In addition, the basic structure of the air-clutch part is so complexthat it has many parts which need to be remodeled when the press isprovided with the air-clutch. Furthermore, as the price of theair-clutch is high, if the conventional model is to be converted into anew one having the air-clutch, then this should be carried out byspecialized persons. Therefore, because of the financial losses due toidle time due to conversion and the high cost incurred by conversion,the conventional press is still used and the danger of accidents istolerated.

SUMMARY OF THE INVENTION

The present invention is presented to solve the aforementioned problemand it is an object of the present invention to provide a sudden brakingapparatus using braking system disposed at the crank shaft of the press,by which the operation of the slide block can be braked instantaneously,thereby preventing operator's accidents, reducing the manufacturingcosts and achieving easy conversion as well as achieving promptoperation due to its being controlled directly and not through a largegear.

In order to achieve the aforementioned object, the present inventioncomprises a circular guide set up to the crankshaft and having a brakelining at the side of press frame, a radially toothed gear at the otherside and a groove taperingly formed along the side of the circumferencein the central part of the guide body; a clutch plate having a radiallytoothed gear matching the radial toothed gear fixed to a large drivinggear; and a fork having one pair of rollers installed on the end partsof both ends of the fork for free rotation and installed to thesupporting frame in order to enable the fork to shift the circular guideusing a hydraulic cylinder through an operating rod. In this way thecircular guide can then be shifted, which enables the up and down motionof the slide-block to stop suddenly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an outline cross-sectional view showing a sudden brakingapparatus for a press according to the present invention;

FIG. 2 is a perspective view of the main part so as to explain thebraking principle according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, the present invention will be explained in detail withreference to the accompanying drawings.

As shown in FIG. 1, the present invention comprises a supporting frame 2fixed vertically to a base 1, a rotational axis 3 set up horizontally tothe upper part of the supporting frame 2, a flywheel 5 provided with apulley 7 mounted to one end part of the rotational axis 3 and connectedto the rotational axis (not shown) of the driving motor 6 through apulley 4 and a belt 8. A small gear 9 is mounted at the other end partof the rotational axis 3 and engaged with a large gear 10 describedlater so that torque is transmitted from the flywheel 5 to the largegear 10.

Furthermore, a crankshaft, disposed below the rotational axis, isdivided into two parts 11 a, 11 b, which have a polygonal section and acircular section respectively. The crankshaft 11 a, 11 b is installed inparallel with the rotational axis 3 by means of a bearing(not shown).

In addition, the crankshaft 11 a, 11 b is connected with a cam 14installed to a crank-rod 13 which enables the slide-block 12 to elevate.A circular guide 19 is disposed at polygonal of the crankshaft 11 b. Agroove 15 is formed taperingly along the side of the circumference inthe middle part of the surface of the circular guide 19, a brake lining16 is attached to one side of the circular guide 19 and on the otherside corresponding to this the radially toothed gear 18 is installed byjointing means such as a bolt 17.

Furthermore, a large gear 20 equipped with a clutch plate 22 on whichthe radially toothed gear 21 is fixed by jointing means such as a bolt20 with a shape matching the radially toothed gear 18 disposed on thecircular guide 19 is set up to rotate freely at the end part of one sideof the crankshaft 11 b as shown in FIG. 2, and this large gear isengaged with the small gear 9.

In addition, a fork 24 is located over the circular guide 19, and thefork 24 moves backward(left) and forward(right) according to thestretching action of a hydraulic cylinder mounted on the upper part ofthe supporting frame 2. The fork 24 is connected as one body to anoperation rod 26 of which the body 25 is in the shape of a horse hoof,and is set up vertically to the piston rod 29 of the cylinder. To bothend parts of the body 25, one pair of rollers 28 are mounted through ashaft 27 and the rollers 28 constitute a section of a circular coneshape which has the same slope as the oblique section of the groove 15.

In FIG. 1, the roller part(A,A′) are shown at the position of 90° C.rotation, in order to display the total parts.

Furthermore, in the entry part of the mold of the sudden brakingapparatus for the press according to the present invention, a sensorsuch as a photo sensor(not shown) is installed to be connected with thecylinder 23 electrically. Consequently, during the elevating motion of aslide-block 12, in the event of dangerous situations such as when a handis held between the mold owing to an operator's carelessness and so on,the sensor perceives this situation and makes the piston-rod 29 movebackward by applying the control power to the cylinder 23. Any of eithera hydraulic or a pneumatic pressure may be used as a working fluid.

The operation and effect according to the present invention are asfollows.

The sudden braking apparatus for the press according to the presentinvention is characterized in that if the sensor detects a dangeroussituation and makes the cylinder 23 work, then the fork 24 enables thecircular guide 19 to move, which artificially prevents the large gear 10from rotating and consequently enables the operation of the slide-block11 installed to the crankshafts 11 a, 11 b to stop promptly.

That is, if the press 29 is turned on, then a driving motor 6 operatesand transmits its torque to the flywheel 5 through the belt 8, whichenables the small gear 9 mounted to the rotational axis 3 and the largegear 10 engaged with the small gear 9 to rotate at the same time.

Furthermore, under such conditions, if the cylinder is made to moveforward(right) by operating a switch such as a foot switch installed tothe press 29, then the fork 24 being pushed out by the operation rod 26and the circular guide 19 moves in the direction shown in the dottedline in FIG. 2, that is, in the direction of the large gear 10.

Accordingly, the rotational force of the large gear 10 is transmitted tothe crankshaft 11 b owing to the fact that the radial teeth 18,21 areengaged with each other and so the slide-block 12 elevates upward anddownward by means of a cam 14 which enables the press to work thetarget.

Furthermore, during the operation of the press, if dangerous situationsarise such as the operator's hand being held between the mold, then dueto the sensor which perceives this situation, the required control poweris applied to the cylinder 23, which makes the piston rod 29 movebackward. Following this, the fork 24 is pushed in the direction of thesupporting frame 2 which is the direction shown in the solid line inFIG. 2, through the operation rod 26, which causes the separation of theradial teeth 18,21 and as a result of the separation, the force ofinertia of the flywheel 5 can not be transmitted to the crankshaft. Inaddition, the lining 16 mounted on the circular guide 19 sticks to theside wall of the supporting frame 2, so that it controls the rotation ofthe crankshaft 11 b. As a result, the rotation of the circular guide 19and the crankshaft can be suddenly halted. Accordingly, it is possibleto stop the elevating motion of the slide-block 12 suddenly.

Meanwhile, the roller 28 installed to the fork 24 which moves backwardand forward by the operation rod 26 comprises a section of a circularcone shape which has the same slope as the oblique section of thetapered groove 15 of the circular guide 19, so that it is possible toreduce to a minimum abrasion owing to friction with the groove 15 in theevent of moving back and forth. Therefore, the fork can be shiftedsmoothly without frictional resistance with the circular guide 19.

The present invention can be realized in various ways without departingfrom the sprit and scope of the invention. In addition, the presentinvention is not limited to the illustrated and explained embodiment.All variations within the above description and following claims will beincluded in the scope of the present invention.

What is claimed is:
 1. A sudden braking apparatus for a press comprisinga driving motor (6), a flywheel (5) connected to the motor through apulley (7) and a belt (8), a small gear (9) connected to the flywheelthrough a rotational shaft (3) installed horizontally to a supportingframe (2), a large gear (10) engaged with the small gear and installedon a crankshaft (11 b) of the press, and a cam (14) mounted at thecrankshaft (11 a, 11 b) and connected to a slide-block (12) via a crankrod (13), characterized in that the apparatus comprises a circular guide(19) slidably connected to the crankshaft (11 b) to rotate therewith andhaving a brake lining (16) on one side of the guide (19) facing thesupporting frame (2), a radial toothed gear (18) located on the oppositeside of the guide and a tapered groove (15) radially extending inwardlyfrom the circumference of the guide; a clutch plate (22) having a radialtoothed gear (21) matching the radial toothed gear (18) and fixed to alarge gear (10) for rotation about the crankshaft (11 b); and a shiftingmeans which enables the circular guide (19) to move horizontally, withthe shifting means mounted between the circular guide and the supportingframe (2), wherein the shifting means comprises a fork (24) installed onthe circular guide (19) and connected to a cylinder (23) through anoperating rod (26) so that the operation rod (26) and the fork (24) canshift the circular guide (19), and rollers (28) mounted on both ends ofthe fork (24).